Deep vein thrombosis main risk not from air travel

August 17, 2009

We are all aware of the risks from DVT on long-haul flights, but it seems that it might have been overestimated according to researchers at the very wonderfully named German Institute for Quality and Efficiency in Health Care. They have found that DVT is very unlikely in healthy travellers, so you could ditch those unattractive flight socks, but that there is another – and very real – risk. If you have had an accident where you have to wear a cast or splint then that can mean an increased risk of DVT in the leg and pelvic area.

Why is it a problem?

Blood clots have the ability to travel to the lungs, leading to pulmonary embolism, and if for any reason you are unable to move your legs regularly, then the blood flow through your veins is slower than usual. As a result, blood may clump together, forming a blood clot which can lead to DVT. Having a pulmonary embolism can reduce the supply of oxygen to the body’s cells, overstrain the heart and even cause heart failure.

Wearing a cast or splint increases the risk of DVT

You know that if you have to wear a cast or splint that you will usually suffer unbearable itching, but most people do not know that this also increases the risk of DVT. The advice from Professor Sawicki, lead researcher in the study, is that to prevent serious complications, it is important to get back on your feet and move around again as soon as possible and medically advised. If you really can’t move then your doctor may prescribe anticoagulants to reduce the blood’s ability to clot.

If you prefer a natural approach then there are a number of foods and supplements that are known to thin the blood. These include foods with high amounts of aspirin like substances called salicylates, omega-3 fatty acids, foods with natural antibiotic properties such as raisins, cherries, blueberries, grapes, strawberries and oranges and vitamin E supplements. You might also want to avoid foods that are high in vitamin K as that helps the blood to clot and so is counter-productive. These foods include spinach, broccoli, brussel sprouts, cabbage, lettuce and peas.

But isn’t air travel the main risk?

Surprisingly, even in higher-risk groups, the risk of air-travel-related thrombosis is still well below half a percent. Research on millions of air travellers has revealed that only about 2 to 5 out of every 10,000 people who took a flight longer than 6 to 8 hours developed DVT that caused symptoms (at the most 0.05%). Even people who had a higher risk – for example, because they had large varicose veins or were very overweight – were not highly likely to develop deep vein thrombosis: only 20 out of every 10,000 travellers were affected (0.2%). Nor was there any evidence to show that people on short flights of less than 4 to 6 hours had an increased risk of thrombosis.

If you would rather be safe than sorry – and you did invest in those special compression flight socks – then the advice is that you will lower your risk by putting them on at least 2 hours before the flight and keep them on throughout the entire journey.